In one conventional form of microwave oven, a sensor is provided for determining the cooked condition of the food and for terminating the cooking operation upon determination of a preselected sensed value.
In one form, the sensor comprises a moisture sensor arranged to determine the humidity of the air being exhausted from the oven cavity. In another form, the sensor comprises a gas sensor for determining a gas concentration of reducing gases generated by the heating, such as methane, ethanol, isobutane, carbon monoxide, and hydrogen.
It is further known to heat the food under the control of such sensors in a two-step process wherein the first step is determined by the sensor sensing a preselected value and continuing the cooking operation for a second period of time based on the first period of time. The cooking operation is normally caused to be terminated upon the food being cooked to subjacent its boiling point.